Concrete floor come away from wall

We put a new floor into an existing grain shed 3 years ago and due to shrinkage theres a gap about 3cm wide all the way around. We've tried putting cement into it but the grain bucket lifts it away once its become brittle. Any ideas of something better? Concrete isn't any option because the gap isn't big enough for it to bind together and a local concrete guy has had a look saying he'd need to cut away about 2ft for it to stand a chance and even then he wasn't keen.

I've had floors shrink about 1-2cm and just filled those with panel mastic. Works well and stays flexible in case of further shrinkage/expansion. Could work out expensive if filling 4" wide gaps though.

I've had floors shrink about 1-2cm and just filled those with panel mastic. Works well and stays flexible in case of further shrinkage/expansion. Could work out expensive if filling 4" wide gaps though.

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Typo now corrected. 3cm average.
I tried the panel mastic initially but it didn't seem to stick very well and when dried was like a window wiper blade.

I agree with Steevo, panel mastic is a good option, depending on area size though.

As for your grain bucket pulling the cement out, if you have a bucket where the wearing edge is wider than the bucket itself, cut it back flush with the sides. I've had this problem before with a shed that was once used as a silage pit and had wooden sleepers on one side wall, the wearing edge would get under the bottom sleeper when scraping tight to the edges and lift the whole lot up.

I had this problem, it wasn't shrinkage though, the walls were pushing out as the walls weren't tied into the floor.
No one could tell me how to stop it happening so I attached another barn to it and concreted it properly
The gap was increasing every year, it's now stopped.
Get a long straight edge and spirit level, you might be surprised by how far out of upright the stanchions are.

I had this problem, it wasn't shrinkage though, the walls were pushing out as the walls weren't tied into the floor.
No one could tell me how to stop it happening so I attached another barn to it and concreted it properly
The gap was increasing every year, it's now stopped.
Get a long straight edge and spirit level, you might be surprised by how far out of upright the stanchions are.

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We've checked them and its definitely the floor as its also coming away from a central concrete panel wall. Apparently concrete mixes with fibres in for strength shrink more than basic concrete. Its also got underfloor tunnels in it that are sending heat which hasn't helped matters.

We've checked them and its definitely the floor as its also coming away from a central concrete panel wall. Apparently concrete mixes with fibres in for strength shrink more than basic concrete. Its also got underfloor tunnels in it that are sending heat which hasn't helped matters.

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Keep an eye on it.
The floor on the new barn hasn't shrunk more than 5-10mm.
, in fact I don't think there's a gap along the concrete panels at all.

We put a new floor into an existing grain shed 3 years ago and due to shrinkage theres a gap about 3cm wide all the way around. We've tried putting cement into it but the grain bucket lifts it away once its become brittle. Any ideas of something better? Concrete isn't any option because the gap isn't big enough for it to bind together and a local concrete guy has had a look saying he'd need to cut away about 2ft for it to stand a chance and even then he wasn't keen.